Stainless steel screws

[mdryden]

Hello. Is it ok to use stainless hardware on the roof of my trailer? I resealed my winegard antenna and was going to replace the screws with stainless. The screws do go into aluminum and I was told that this can cause corrosion?

[Retired_JSO]

Thousands of very expensive boats are built yearly bolting aluminum T tops to fiberglass using stainless fasteners.

[Super_Dave]

MNRon wrote:
Mdryden - you’re good, no worries

Yep, you'll need to find a new repair to worry about, you're good here.

My boat is aluminum and full of SS screws from accessories that I have added.

[Dave_H_M]

I have replaced a lot of rusty screws with stainless and gun the hole full of silicon (color or clear your choice) and never had to look back.

if you are allergic to silicon use the sealer of your choice.

[MNRon]

Mdryden - you’re good, no worries

[mdryden]

They were not self tapping screws. They resembled just a typical screw only they had a head on them that were painted white.

[EgorKC]

If they were in the stainless tapping screw section of the hardware store they are in all probability 18-8. They would only carry 410 in drill screws that had a drill point. If they were tapping screws you should be ok. I would also note that if reactive embrittlement occurs (on 400 series fasteners into aluminum) it Always happens within 24-48 hours per every expert I have read on the subject.
I would not recommend using a standard zinc plated steel screw in aluminum as the risk of the embrittlement is even greater. And corrosion will likely occur even if you cover with a sealant. Expansion and contraction of all the components will allow some moisture in the form of humidity to make its way into the joint.
Greg

[mdryden]

I picked up the screws at my local hardware store so I have no idea what grade they were. All screws were covered in dicor. I used them to replace the ones that were holding the transition trim on. From the factory the transition bars were secured to the luan plywood and I ended up having to go into the aluminum substructure. I needed 2 in long screws otherwise I would have just replaced them with some from a rv store. So do I need to remove them if they are not the right grade? Last year I resecured the roof rack also since it was only mounted to the luan and the standoffs were loose. I used stainless screws there as well and secured to the substructure. Again everything is covered in dicor. Please advise and thanks for all the help!

[Cummins12V98]

Waste of $$$ if you are going to seal over the screws.

[ppine]

Use the right screws. SS is not the best with Al.
I just removed the bronze wood screws on my wood and canvas canoe. They are 67 years old and in perfect shape. After clearing out the paint in the slots, they are going back on the boat.

[EgorKC]

30+ years in the fastener industry. As long as you use a 300 series (commonly known as 18-8 stainless) you are ok. Do not under any circumstances use a 400 series stainless such as 410. 302, 304, 305 are the most common 18-8 used in fasteners.
Greg

[freetime58]

The hardware and fasteners used on the millions and millions and millions and millions of aluminum boats out there is stainless steel.....just sayin!!!!

[Durb]

Stainless into aluminum is certainly better than zinc on aluminum. Realize that zinc plating is micro-thin and will corrode away in less than a year. Stainless into aluminum are both solids so have mass. Electrolysis also needs an electrolyte (water); keep the contact point dry and you won't have a problem. I've replaced all the screws holding the moldings onto my trailer with stainless (over 600). Never a problem.

[MNRon]

I’ve also put many (hundreds) of stainless screws into aluminum, on RVs and a couple pontoon boats. Certainly the screws into aluminum on the boats saw water. Have never had an issue.

[time2roll]

Never had any trouble with stainless fasteners and corrosion.